#define  _CRT_SECURE_NO_WARNINGS 1
#include "Stack.h"

void StackInit(Stack* ps)
{
	assert(ps);
	ps->a = NULL;
	ps->capacity = ps->top = 0;
}

void StackPush(Stack* ps, STDateType x)
{
	assert(ps);

	if (ps->top == ps->capacity)
	{
		int newcapacity = ps->capacity == 0 ? 4 : ps->capacity * 2;
		STDateType* tmp = (STDateType*)realloc(ps->a, sizeof(STDateType) * newcapacity);
		
		if (tmp == NULL)
		{
			perror("realloc fail");
			exit(-1);
		}

		ps->a = tmp;
		ps->capacity = newcapacity;
	}

	ps->a[ps->top] = x;
	++ps->top;
}

void StackPop(Stack* ps)
{
	assert(ps);
	assert(ps->top > 0);

	--ps->top;
}

STDateType StackTop(Stack* ps)
{
	assert(ps);
	assert(ps->top > 0);

	return ps->a[ps->top - 1];
}

int StackSize(Stack* ps)
{
	assert(ps);

	return ps->top;
}

bool StackEmpty(Stack* ps)
{
	assert(ps);

	return (ps->top == 0);
}

void StackDestroy(Stack* ps)
{
	assert(ps);

	free(ps->a);
	ps->a = NULL;
	ps->top = ps->capacity = 0;
}